Corus Construction & Industrial
Steel-framed car parks
Contents
Avebury Boulevard multi-storey car park Milton Keynes
Contents
Contents 5
Introduction
Acknowledgements
Attributes of good car park design
This is the third edition of the Steel-framed car parks
Advantages of steel construction
brochure, and Corus would like to acknowledge the input of all previous contributors, specifically:
6
Outline design Dynamic efficiency
Compilers of the first edition published in 1995.
Flow patterns
• Bernard WJ Boys, formerly British Steel plc and the
Circulation design
• David Dibb-Fuller, Partner, Gifford and Partners
Steel Construction Institute 7
Ramp width and slope Car park layout
Compiler of the second edition published in 1998. • Colin S Harper, formerly British Steel plc now Corus.
9
Structural form Foundations
Corus would also like to recognise the contribution of
Column positions
the following organisations to the production of the third
Floor and frame solutions
edition of this publication:
Underground car parks Vehicle safety barriers
• The Steel Construction Institute
Deflection
• Bourne Parking Ltd.
Dynamic performance
• Caunton Engineering Ltd.
Stability
• Clugston Construction Ltd. • Hill Cannon (UK) LLP
16 Fire resistance
• Severfield-Reeve Structures Ltd.
18 Durability The steel frame Concrete floors Metal decking Waterproofing Refurbishment 21 Aesthetic design 22 Commercial viability 23 Latest developments Demountable car parks Wholly automatic multi-storey car parks 24 Sizing data sheets 28 Case studies 34 Bibliography 35 Support for the construction industry from Corus Construction & Industrial
Steel-framed car parks
3
Avebury Boulevard multi-storey car park Milton Keynes
Introduction
Introduction The multi-storey car park is a unique style of building; one in which all elements of the structure are normally exposed to the public.
This publication gives examples of good practical
Steel is also an ideal material for satisfying the
design that enable the structure to blend with all
requirements of ‘Rethinking Construction’:
environments whilst utilising the inherent versatility, elegance and economy of a steel frame.
• Reduced costs • Reduced time on-site
Fundamental design information is given to illustrate how
• Off site fabrication of primary structure
steel, with its ability to accommodate long clear spans
• Increased productivity
and minimise column sizes, can create aesthetically
• Certainty of budget and time
pleasing, economic, secure, user-friendly car parks.
• Improved efficiency in the use of materials • Reduced wastage
This guide is intended to assist the designer with the
• Safer construction
preparation of budget schemes, without the need for
• Improved quality
complex calculations at the outset. It does not however, relieve the designer of his responsibility for providing full
Steel solutions also have excellent sustainability
design data for the built structure. Further guidance is
credentials:
available in the Institution of Structural Engineers publication ‘Design recommendations for multi-storey and underground car parks’ (THIRD EDITION).
• Composite construction uses materials more efficiently • Minimised waste
Attributes of good car park design
• Recycled and recyclable material
• Easy entry and egress to car park and stalls
• Adaptable construction
• Uncomplicated and logical traffic flow
• Lightweight construction leads to more efficient
• Unimpeded movement • Light and airy
foundations than for other forms of construction • Long life product
• Low maintenance • Safe and secure Advantages of steel construction This guide will demonstrate that steel construction is ideally placed to satisfy all the requirements of good car park design. Steel is: • Ideal for long spans • Lightweight • Robust • Fire resistant • Easily maintained • Vandal resistant • Minimalist • Economic
Steel-framed car parks
5
Outline design
Outline design The dimensions of large, standard and small size cars Stall width
the Institution of Structural Engineers publication ‘Design recommendations for multi-storey and underground car parks’ (THIRD EDITION). These
Bin width Aisle
are well established and are presented in Table 4.1 of
dimensions form the basis of the geometry required for stalls, aisles and ramps. The minimum dimensions are based on the standard car and the bin size on the parking angle and stall width. This is shown in Table 1. Table 1. Effect of varying parking angle on parking bin requirements
Figure 1. One way flow, angled parking
Parking angle
• Two-way flow systems are more familiar to the user and if
Stall width (m) parallel to aisle
Aisle width (m)
2.3 2.4 2.5
3.25 3.39 3.54
3.60
60°
2.3 2.4 2.5
2.66 2.77 2.89
75°
2.3 2.4 2.5
45°
Bin width (m) (stall length 4.80m)
properly designed can achieve a higher flow rate than one-way systems. They require marginally more space
13.65 13.80 13.95
and are therefore less structurally efficient than one-way
14.85 14.95 15.05
parking as their use with angled parking can cause
4.20
2.38 2.49 2.59
4.98
15.45 15.50 15.55 15.60 16.55
90°
All
All
One way aisle 6.00
90°
All
All
Two way aisle 6.95
systems. Two-way systems are best used with 90° confusion to the driver.
Stall width Bin width Aisle
Stall width (m)
Dynamic efficiency The dynamic efficiency of a car park depends on the ease with which entry, egress and parking can be achieved. The general principle should be that cars cover as many stalls as possible on entry and as few as possible on exit. The layout of the exits and the size of the reservoir capacity are other major factors when considering dynamic efficiency. Flow patterns There are two flow patterns used in modern car park construction: one way and two-way flow. These can be combined with either 90° or angled parking. • One-way flow systems, if used with angled parking, provide a very good solution to the parking problem. They ensure easier entry and exit to stalls and allow significant flow capacities to be achieved with the self-enforcing flow pattern. Difficulties can arise when the intended flow is ignored and therefore good signage is required.
6
Steel-framed car parks
Figure 2. Two way flow, 90° parking
Circulation design
Circulation design Ramp width and slope
Split-level layouts (Figure 3) have good dynamic flow
The widths of the ramps should usually be no less than
rates and excellent structural efficiency. They can be
3.5m for a single ramp and 7.0m for a double ramp. It is
used with one-way and two-way circulation patterns
recommended that ramp widths are kept in line with
and a variety of ramp arrangements to achieve the
stall widths, for example with single flow traffic, the
desired performance.
ramp would be two stall widths wide and for two way traffic flow, three stall widths wide.
This is probably the most popular layout in the UK for car parks with row capacities greater than 24 cars. Entry
The slope of the ramp is dependent on the clear
and exit traffic are separated and the flow pattern is
headroom (2.1m minimum) and the structural zone. The
simple and uncomplicated. When built in steel, with
growth in popularity of the larger multi-purpose vehicles
column free spans, this layout will give the best
(MPV’s) has had an effect on the minimum clear height
combination of economy and operating efficiency.
and ramp length requirements. The shallower and wider the ramp, the better it will meet the needs of users. However less steep ramps are longer. Typical slopes range from 1:6 to 1:10. Steeper gradients may be used if transitions are provided at the top and bottom of the slope. Refer to the Institution of Structural Engineers publication ‘Design recommendations for multi-storey and underground car parks’ (THIRD EDITION) for detailed guidance on rampwidths and slopes. The split-level system, shown in Figure 3, offers a method of reducing ramp length, whilst keeping the gradient within reasonable limits by staggering the parking levels by half a storey height. Figure 4. Flat deck layout
Flat deck layouts (Figure 4) are becoming increasingly popular for their simplicity of construction, clean lines and ease of use. They are particularly suitable in situations where the floor levels have to be matched to another building. This layout is less efficient than the split-level arrangement but can have comparable dynamic capacity for infrequent users. However the larger search paths can be frustrating for frequent users where a ‘parking ramp’ solution may be more acceptable. Figure 3. Split-level layout
The layout illustrated (Figure 4) would be used for Car park layout
smaller car parks where the dynamic capacity is not
There are many layouts used for multi-storey car parks,
critical. Two-way flow is used with external rapid entry
each offering specific advantages to the user and
and exit ramps.
operator. The layouts indicated are those most commonly used in the UK. All are eminently suited to a steel-framed solution, which will be competitive on price and provide excellent performance.
Steel-framed car parks
7
Circulation design
The parking ramp shown is a single ramp with two-way flow. It offers ease of use combined with efficient usage of space. External ramps may be added if rapid exit from the park is required. In this case a one-way system would be preferred. Whichever type of layout is chosen, a number of key principles should be followed: • Keep it simple. What looks like a clever solution could be difficult for the user • Minimise the workload on the driver and avoid confusion as to where to go and what to do. This is solved partly by signs but mainly by good design. • Cover as many stalls as possible on the entry route Figure 5. Parking ramps
• Pass as few stalls as possible on the way out • Separate inward traffic from outward traffic if possible,
Parking ramps (Figure 5) may be used with great success where frequent users are the prevalent customers, for example, a large office. Their main advantage is that the user must pass all stalls on entry to the car park, resulting in a rapid search path and less frustration. Users can be disadvantaged when exiting the car park unless an express exit is provided.
Green Park Reading
without causing additional complications • Circulate to the right if possible so that the driver is on the inside of the turn
Structural form
Structural form The structural design of a car park will usually determine
However there may be occasions, for example, where
its quality as a user-friendly structure. The structural
the car park is beneath another form of structure with a
form should provide:
different span arrangement, where internal columns must be used (Figure 7). This arrangement has an
• Ease of entry and egress to and from stalls so that
impact on the column cross centres and a comparison
users can gain rapid entry and exit without the risk of
of possible geometry for clear span and propped
damage to vehicle or injury to person.
alternatives is presented in Table 2.
• Few obstructions to movement. The driver should be guided through the park without encountering severe obstructions such as columns in the drive path and badly parked cars caused by inefficient design or layout. • A light and airy environment. The environment the car park provides will often determine how profitable it is. A light and airy environment should be one of the major goals of the car park designer. Steel is ideally placed to provide this type of environment because of its lightweight nature and long span capabilities. This can be further enhanced if open web sections are chosen. See case study 2. • A safe and secure environment. Today, personal security is high on the list of priorities for any building; car parks are no exception and due to their public nature they must be safe for users and their vehicles.
Figure 6. No internal columns to impede traffic flow
A building with minimal internal structure will help to enhance the feeling of security by making the area as open as possible with few barriers to sight lines. The light and airy environment made possible with steel will help to enhance the feeling of security required of these buildings. Foundations The design loading for car parks is given in BS 6399, which specifies an imposed loading of 2.5kN/m 2 for the parking areas and ramps. The loading on foundations is greatly influenced by the material chosen for the frame. Steel is the lightest practical construction material and will often allow the use of simple foundations where other, heavier materials will not. The type of foundation required is often the deciding factor on whether a project is viable. Steel is often the only viable
Figure 7. Alternative positions of columns impede traffic
construction material for multi-storey car parks. Column positions The desirable attributes indicated above will only be completely fulfilled if there are no internal columns (Figure 6). If steel is chosen as the frame material a clear span solution can be used for the majority of car parks.
Steel-framed car parks
9
Structural form
Table 2. Effect of internal columns on overall width No. of cars between columns
Column cross centres option (2.4m stall width)
Reduced column cross centres for clear span
2
(a) 2.400 x 2 } (b) +0.300 x 2 } = 5.7m (c) +0.150 x 2 }
4.8m
3
(a) 2.400 x 3 } (b) +0.300 x 2 } = 8.1m (c) +0.150 x 2 }
7.2m
4
(a) 2.400 x 4 } (b) +0.300 x 2 } = 10.5m (c) +0.150 x 2 }
9.6m
(a) Stall width (b) Clearance to column (c) Half column width
It is generally preferable to arrange longitudinal column and beam spacings to coincide with parking stall widths; the equivalent of one, two or three stall widths are the
Shear Connector Mesh Reinforcement
Transverse Reinforcement In-Situ Concrete A
most commonly used. Using a single width has the advantage of visually separating the stalls for the driver, but it is not suitable when using internal columns. With column spacing of two stall widths it is generally only necessary to use secondary beams when shallow profile
A PCC Slab
steel decking is used to form the slab. Other slab solutions may require secondary beams when the column
Steel Beam
spacing is in excess of two bay widths. Secondary beams are used to avoid propping of the floor during construction, to limit depth of construction and ensure economy of design. Floor & frame solutions A variety of floor systems can be used in multi-storey car park construction. The ultimate choice will depend upon
View on A-A Figure 8. Composite beam with PCC hollow core slab
many factors, such as height restrictions and structural layout. Five of the most common types of floor
Figure 8 shows hollow core pre-cast units used
construction used in steel-framed car parks are shown
compositely with the steel beams. To achieve composite
(Figures 8-12). With all the illustrated systems the steel
action, alternate cores of the precast units must be
beams may generally be designed either compositely or
broken out and filled with in-situ concrete for the
non-compositely. The exception is where precast units run
effective width of the slab. Additional transverse
parallel to the primary beam, in which case the primary
reinforcement is also required. A concrete topping
beam will be a non-composite design.
would normally be used to give adequate resistance to moisture penetration and to tie the pre-cast units together to form a monolithic floor slab. Detailed guidance is available in SCI publication P287, 'Design of Composite Beams Using Precast Slabs'. The system has the advantage that wider spacing of main beams can be achieved because of the pre-cast unit's spanning capabilities, and low self weight. Speed of construction will be improved over a solid slab, leading to greater cost savings on the scheme. In the non-composite version of this system the cores of the
10 Steel-framed car parks
Structural form
pre-cast units do not require to be broken out, this leads Reinforcing Mesh
to faster construction times at the expense of greater steel weight. The metal deck solution, shown in Figure 9, has been
Shear Connector Metal Deck
A
used for a small number of car parks in the UK. As well as performing a role as part of a composite slab, the metal deck also acts as permanent formwork to improve speed of erection and reduce cranage requirements compared with the other systems described. The
In-Situ Concrete
maximum unpropped span of these types of decks is around 4.5m (consult manufacturer's literature for exact
Steel Beam
details), therefore the spacing of the main beams cannot be greater than one stall width unless secondary beams are used. When metal deck is used in conjunction with composite A
beams, through deck welding of the shear studs is beneficial because it enables continuous sheets of decking to be laid on the steel beams prior to fixing the studs. It may also enhance the way in which the decking behaves as transverse reinforcement adjacent to the studs. However, in the potentially corrosive environment of a car park, the need, when using through deck welding, to keep the upper surface of the beams free of paint (to avoid contamination of the stud welds) may be unacceptable. This leaves the designer with four options: • Use shear connectors that are attached to the beams without the need for welding. A number of connectors that use shot-fired pins are available.
View on A-A
• Weld the studs to the beams in the fabrication shop, prior to applying the corrosion protection. With this
Figure 9. Composite beam and metal deck
solution the decking is best laid in single span lengths and butted up to the studs. This makes the decking less structurally efficient and requires stop ends to prevent the in-situ concrete escaping through voids. Alternatively, holes may be punched in the deck so that it can slot over the studs, but this may be more difficult to achieve in practice. • Use non-composite beams. • Use a combination of non-composite secondary beams and composite primary beams. The decking can then be laid in continuous lengths across the secondary beams, which are normal to the span of the primary beams.
Steel-framed car parks 11
Structural form
shear connectors welded to the top flange of the steel beam. These should be welded ‘in the shop’ so that corrosion protection can be applied. Transverse reinforcement will be required and additional bars may also be required at the stud location to act as bottom reinforcement.
Gap filled with expanding grout and covered with strip waterproof membrane Shear connectors Strip waterproof membrane
Deep decking enables the elimination of secondary
Galvanised reinforcing bars set into pre-cast slab
beams because it can span up to 9.0m. Deep decking
Steel beam
Figure 10. Slimdek® and deep decking
110mm thick pre-cast concrete deck with brushed finish
will provide the maximum benefit when used with Slimdek ®, as shown in Figure 10, typically spanning around 9.0m. Figure 12. 'Montex’, pre-cast slab system
A variation on the pre-cast slab design is the 'Montex' system illustrated in Figure 12 which is a proprietary Shear connector Reinforcing mesh
In-situ concrete topping Reinforcement
design using special slabs with hooped bars emerging from the ends of the units. These are used to tie the system together as illustrated in Figure 12. The void is filled with in-situ concrete and then covered with a strip waterproof membrane.
Transverse reinforcement
PC concrete slab
Underground car parks Steel beam
Steel sheet piles are ideal for producing an efficient, cost effective and quick retaining structure for underground car parks and deep basement car parks. Floors can be designed to act as struts for the finished structure, which can be utilised in the ‘Top Down’ construction method. This combined with the ability of a steel sheet pile
Figure 11. Composite beam with composite PCC slab and topping
Figure 11 shows a composite beam with composite pre-cast concrete slab and topping. The pre-cast slab in this case is solid and usually only 75mm to 100mm thick. This spans between beams, the maximum span being around 5m, allowing main beams to be spaced at two stall widths, without propping of the slab during construction. Composite construction is achieved with
12 Steel-framed car parks
retaining wall to accept vertical bearing loads make this form of construction particularly effective for car parks beneath new buildings. Further information on underground car parks is contained in the Steel Construction Institute publication SCI-P275: Steel Intensive Basements.
Structural form
Figure 13. @Bristol underground car park.
Figure 14. Pre-cambered cellular beams as used at the Buttercrane Centre car park, N. Ireland.
Vehicle safety barriers
other situations because users are either in motion
All car parks should be fitted with adequate vehicle
themselves, by walking, or sat in a car and isolated from
safety barriers to prevent accidental damage to the
external vibration by the suspension.
structure and restrain out of control vehicles. Edge barriers in particular should be adequate to restrain
Traditionally, steel-framed car parks have been designed
vehicles and be of a height and design, which will
using a minimum frequency as a sole measure of
safeguard small children. BS 6180: 1999 'A code of
dynamic performance. SCI publication P076 suggests
practice for barriers in and about buildings' may be
the minimum frequency of the floor (including the
of assistance.
concrete slab, primary and secondary beams, where appropriate) should not be below 3Hz. More recent
Deflection
guidance from the Institution of Structural Engineers
Where clear span construction and high strength steels
suggests an increase, but it appears that this is not
are used for the main beams, deflection may govern the
based on any adverse comment from users or owners.
design. These beams may therefore be pre-cambered to compensate for dead load deflection and to minimise
For vibration, consideration of natural frequency alone
the risk of ponding, when in-situ concrete solutions are
can be misleading, as it is the amplitude of vibration
used. An additional pre-camber may be introduced to
that most people feel. The amplitude can be expressed
compensate for a proportion of the live load deflection
in terms of displacements, but, in practice, this can be
(usually up to 1/3). This has the advantage that the
difficult to measure. As a consequence, most modern
beams have a slight upward bow, which avoids the
Standards describe the sensitivity of human exposure to
optical illusion of a heavily deflected beam when it is, in
vibrations in terms of acceleration amplitudes. In BS
reality, level. The theoretical deflections, allowed for in
6472, accelerations are expressed relative to a ‘base
pre-cambers, do not always occur and care must be
value’, which is adjusted with frequency according to
taken to ensure that any permanent set does not
human perception, so forming a ‘base curve’, as shown
impede the efficient drainage of the slab.
in Figure 15. The ratio of the predicted (or measured) acceleration to the base curve value is then defined as a
Dynamic performance
‘response factor’. A variety of response factor values are
The dynamic performance of floors in buildings has
recommended for different floor types, but there are no
become an important issue in recent times, which has
recommended values for car parks in BS 6472.
led to a review of design practice in this area. In buildings such as hospitals, the dynamic performance can be critical, but in buildings such as car parks, where there is an expectation of disturbance from traffic movement, it is much less important. The human perception of movement in a car park will be less than in
Steel-framed car parks 13
Structural form
1.000 70 car park empty car park full
60 12 x base curve
50 Response factor
0.100
4 x base curve
30 20
Base curve
0.010
40
10 0 0 0.001
1
10 Frequency (Hz)
1
2
3 4 Floor frequency, fo (Hz)
5
6
7
100
Figure 15. Vertical vibration curves taken from BS 6472
Figure 16. Car park dynamic performance
To compensate for this ‘omission’ in the British
To demonstrate the level of accuracy in the analysis
Standard, a study was made of 9 steel-framed car parks
presented here, a car park framed with long span
incorporating long spans. All were constructed in the
cellular beams, which has been subjected to vibration
last 15 years, with no adverse comment about the
tests in Atlanta, Georgia, USA, has been analysed using
dynamic behaviour being known. The examples
the same method. The difference between the measured
included 7 car parks with composite beams and pre-
and calculated values of frequency and response factor
cast units (with a concrete topping or asphalt finish),
was less than 10%.
and 2 with composite beams and a concrete slab using metal decking as permanent shuttering. Secondary
The above results clearly show that there has been a
beam spans ranged from 15.6m to 28m, and floor slabs
recent history of car park construction with low natural
spanned between 3.6 and 7.2m. The most onerous floor
frequencies and high response factors, which have
area in each example was chosen to calculate the
received no adverse comment. The study shows that the
natural frequency and the corresponding response
traditional natural frequency value of 3.0Hz can be
factor. An ‘empty’ case (assuming 1.1% damping) and a
maintained for design, and used with confidence. For
‘full’ case (assuming 2.5kN/m imposed loading and
normal steel-framed solutions, the adoption of this value
4.5% damping) were considered.
leads to bare floors (damping 1.1% with no imposed
2
load) possessing a maximum response factor of The results of the study are shown in Figure 16. Floor
approximately 65. This response factor value can be
natural frequencies ranged from 2.8 to 5.18Hz ‘empty’
used as guidance where more detailed calculations are
and 2.2 to 4.2Hz ‘full’. The natural frequencies tend to
deemed to be appropriate. No guidance is given for a
be lower under full loading because of the higher mass
full car park because the characteristics are different
mobilised. Response factors ranged from 3.6 to 64.5 for
and it is considered that design based on the criterion
the ‘empty’ cases and 0.9 to 26.6 for the ‘full’ cases.
for the empty case is sufficient.
The ratio of the natural frequency ‘full’ to ‘empty’ was nearly always about 0.8, which merely reflects a
This section has been concerned with human-induced
consistent ratio of dead loading only to full loading of
vibration, but excitation may be caused by impact from
0.64 for car park construction. Response factors are
cars running over uneven surfaces or discontinuities,
generally higher for the ‘empty’ case, where the mass
such as expansion joints. Careful detailing and
and damping is less.
workmanship should ensure that any joints are level and can be traversed smoothly, and that the gaps are no larger than necessary. Regular maintenance should prevent the wearing surface from deteriorating.
14 Steel-framed car parks
Structural form
Figure 17. Cross bracing as used at the Genesis car park, World Cargo Centre, Heathrow
Stability
A combination of these methods may be used. For
The stability and robustness of a structure is a vital
example, use a rigid frame across the structure and
structural design consideration. Multi-storey car parks
brace longitudinally at the outside edge of the building.
pose a particular problem because they contain few internal walls. This is especially true of demountable
Whichever method of achieving stability is chosen, it is
structures. There are various methods to ensure
important to consider the construction stage of the
structural stability against horizontal forces; two of the
building as well as the completed structure. The floor
most common options are outlined below.
slab in most cases is designed to carry the horizontal forces to the braced parts of the structure. Until this
a) Braced structure. Suitable bays or cores are placed around the building to provide stability in two
plate has gained sufficient strength it may be necessary to provide temporary plan bracing.
orthogonal directions. Bracing may take the form of cross members or eccentric type bracing. In car parks the eccentric bracing can be used across the structure because it allows relatively unimpeded circulation throughout the floor area. An example of a braced car park structure is shown in case study 1. b) Unbraced structure. In this case the frame is designed as 'rigid'. Moments are transferred from beams into columns via moment connections and stability is gained from the stiffness and continuity of the connections. This may result in the need for haunches in clear span construction. Steel-framed car parks 15
Fire resistance
Fire resistance Steel-framed car parks have been rigorously fire tested in a number of countries (Table 3). These tests demonstrate that most unprotected steel in open sided steel-framed car parks has sufficient inherent resistance to withstand the effects of any fires that are likely to occur. Table 3 lists the maximum temperatures reached in open sided car park tests in four countries. These can be compared with the limiting temperatures of 620°C for beams carrying floor slabs and 550°C for columns, at which failure is expected to occur. Open sided car parks are defined in Approved Document B to the Building Regulations 2000 for England & Wales as having open ventilation of at least 5% of the floor area at each level, at least half of which should be in opposing walls. The fire resistance requirements for open sided car parks in the United Kingdom and Ireland are outlined in Table 4. The dominant period is 15 minutes. Most universal beams and columns will achieve 15 minutes fire resistance without added protection although a small number of sections at the lower end of the range, for example the 152 x 152 x 23UC and 127 x 76 x 13UB, will do so only when less than fully loaded.
Section factor (Hp/A) = Heated perimeter/Cross Sectional Area. These are calculated for most common situations in the Corus sections brochure.
The data on limiting section factors can also be expressed as a function of load ratio as defined in
In general, where a section does not have 15 minutes inherent fire resistance, it is usually more efficient to increase the section size than to fire protect.
BS 5950 Part 8, Code of Practice for Fire Resistant Design. A fully loaded beam or column is normally assumed to have a load ratio of 0.6 for the fire limit state. Provided the load ratio is less than 0.6, most universal beams & columns will achieve 15 minutes fire resistance
Table 3. Fire tests in various countries Full scale fire tests
* Increased to 60 minutes for compartment walls separating buildings + Increased to 30 minutes for elements protecting a means of escape ◊ The European Supplement to Approved Document B outlines details of beams and columns, in terms of section factors, which are deemed to satisfy the requirement to achieve 15 minutes fire resistance without protection. I. Beams supporting concrete floors, maximum section factor = 230m-1 or open section beams with a minimum lower flange thickness ≥ 9mm. II. Free standing columns, maximum section factor = 180m-1 or open section columns with a minimum lower flange thickness ≥ 12.5mm. III.Wind bracing and struts, maximum section factor = 210m-1 or flats, angles and channels with a thickness ≥ 10mm or hollow sections with a wall thickness ≥ 6mm. # A note similar to that in the European Supplement to Approved Document B exists in Technical Standards Part D, page 33D. This says that, where the topmost storey of the building is at a height not more than 18m above ground, the requirement for the structural frame will be met by: I. Beams supporting concrete floors, each beam having a maximum section factor = 230m-1. II. Free standing columns, each having a maximum section factor = 180m-1 III.Wind bracing and struts, each having a maximum section factor = 210m-1
without fire protection. The exceptions, and the
Maximum measured steel temperature
maximum load ratios to achieve 15 minutes fire
Beam
Column
resistance for non-composite construction, are provided
UK
275°C
360°C
in tables 5 and 6 on the right:
Japan
245°C
242°C
USA
226°C
–
Australia
340°C
320°C
Table 4. Open sided car parks Requirements from regulations
Height of top floor Up to 30m
Over 30m
England and Wales
15 minutes * + ◊
60 minutes
Scotland
30 minutes #
30 minutes
Northern Ireland
15 minutes * +
Not permitted
Republic of Ireland
15 minutes *
Not permitted
16 Steel-framed car parks
Fire resistance
Table 5. Maximum load ratios for 15 minutes fire resistance – UB exceptions* UB section size
Section factor (Hp/A)
Maximum load ratio to achieve 15 minutes fire resistance
127x76x13UB
285m-1
0.54
152x89x16UB
275m
0.54
178x102x19UB
270m
0.54
203x133x25UB
250m
0.57
254x102x22UB
285m
0.49
254x102x25UB
259m
0.56
305x102x25UB
285m
0.48
305x102x28UB
255m
0.58
356x127x33UB
250m
0.58
406x140x39UB
245m
0.59
-1
-1
-1
-1
-1
-1
-1
-1
-1
* Where design is governed by serviceability, the majority of these sections will achieve 15 minutes fire resistance. This should be assessed on a case by case basis.
Table 6. Maximum load ratios for 15 minutes fire resistance – UC exceptions UC section size
Section factor (Hp/A)
Slenderness ratio*
Maximum load ratio to achieve 15 minutes fire resistance
152x152x23UC
310m-1
81
N/A, Choose next in the section range
152x152x30UC
240m
78
0.36
152x152x37UC
190m
77
0.45
203x203x46UC
205m
58
0.51
203x203x52UC
185m
58
0.58
-1
-1
-1
-1
*Assumes an effective length of 3 metres. The actual failure temperature is a function of the slenderness ratio.
In practice, many sections will have load ratios lower than 0.6. The latest version of BS 5950 Part 8 was published in 2003, after the European Supplement and the most recent version of Technical Standard D. This differentiates between composite and non-composite beams and between different degrees of shear connection. The effect of this will be that composite beams will be assumed to have lower failure temperatures than non-composite beams. This could be taken to mean that some additional beams will not achieve 15 minutes inherent fire resistance when designed compositely. However, composite beams have enhanced robustness because of the effects of continuity in the floors. This has been investigated and the results published in Report No. 75 – Fire Safety in Open Car Parks, published by the European Convention for Constructional Steelwork, which concludes that, in the event of a fire in an open car park, no failure will occur.
Steel-framed car parks 17
Durability
Durability A car park should be designed to give the best possible
top surface of the concrete slab should be protected
return on investment and should therefore be
with an appropriate proprietary waterproofing system.
maintenance free as far as possible. Maintenance
Manufacturers guidance should be followed for the
requirements, and how they should be carried out, are
correct choice of product and application.
described in the ICE publication “The inspection and maintenance of multi-storey car parks”. Maintenance is
Metal decking
of particular importance to ensure that drainage gullies
G275 galvanizing (275g/m2 of zinc) is the standard
and downpipes are clear of debris to enable water to
protective coating for composite steel decking. This
drain efficiently from the car park.
level of corrosion protection to the upper surface of the decking will be sufficient, provided adequate provision
Car parks, by their very nature exist in environments that
has been made to prevent the ingress of water (using
are far from ideal. The air is often contaminated with
reinforcement to control cracking, and waterproofing the
fumes from car engines. The surfaces of the structure
top surface of the concrete). The underside of the
may be sprayed with water, which in winter can be
decking should be given additional protection in the
contaminated by de-icing salts and other highly
form of a pre-applied coating or epoxy paint applied in-
corrosive elements that can percolate through cracks in
situ. Such an additional layer of protection has the
the concrete slab. Although the effect of these can be
advantage that it can be regularly inspected and
minimised by good drainage design, crack control,
remedial work undertaken if required. However, it is
and /or the application of protection to the top surface of
recommended that Corus be consulted on durability and
the slab, it is still necessary to give complete protection
future maintenance issues at an early stage if this
to those components within the car park, which are
solution is to be adopted.
likely to be in close contact with these contaminants. The major elements are the steel frame and the
Waterproofing
concrete, or composite floor slabs.
Car parks require treatment against the effects of an external climate. The car park environment can be very
The steel frame
onerous, especially where aggressive snow and ice
Steel is a durable framing material. It will, if protected
clearing methods are adopted. It is therefore
correctly, give a long life with minimal maintenance.
recommended that at least the top deck of the car park is waterproofed with a traditional bituminous membrane
In most cases all that is required is a repaint at the first
or liquid applied seamless coating. It is also good
maintenance period, which can be 20 to 30 years or
practice to treat other floors to prevent ingress of water.
more, depending on the initial protection specified.
It is important to specify the correct product and ensure
Three suggested treatments are given in Table 7. The
that installation and maintenance are fully in accordance
durability of the protection system is primarily influenced
with the supplier’s recommendations.
by the corrosivity of the environment. The corrosivity categories are based upon those given in ISO 12944
With all floors it’s necessary to provide adequate falls and
Part 2 and ISO 9223.
drainage to prevent the build up of water on the slabs.
Concrete floors
There is a growing trend to use a lightweight roof over
The concrete within a car park is particularly susceptible
the top parking deck. This gives added protection to the
to deterioration, so grade 50 concrete should usually be
top floor of the car park allowing users to park in all
specified. Pre-cast units are generally more durable than
weathers. The aesthetic appeal of a car park can be
in-situ concrete due to factory controlled production
significantly enhanced by this method enabling the park
conditions. It is recommended therefore, that one of the
to blend in with the urban environment. The long-term
pre-cast systems outlined above should be used with a
benefits of reduced maintenance can far outweigh the
limited amount of structural topping. To minimise the
initial cost of this approach. The car parks at Aylesbury
percolation of corrosive fluids through cracks floors
and Guildford typify this method of construction.
should be sloped at 1:60 falls to aid drainage, and the
18 Steel-framed car parks
Durability
Table 7. Suggested corrosion protection systems Car parks Environmental category (Note 8)
C3
C4
C5
System number
B12
E6
E9
C3
20+
25
30
C4
15-20
15-20
25
C5
8-20
12
20
N/A
Blast clean to Sa 21⁄2
Blast clean to Sa 21⁄2
Anticipated durability of the coating system in years and environment categories (Notes 1 & 2)
Shop applied
Surface preparation (BS 7079: Part A1) Coatings (Note 5)
Site applied
Coatings
Relative costs (Note 6)
Hot dip galvanize to BS EN ISO 1461 (Note 3)
Zinc rich epoxy primer
40µm
Zinc rich epoxy primer
40µm
High build epoxy MIO
100µm
One or two coats High build epoxy MIO
200µm
85µm
None (Note 4)
High build epoxy MIO (Note 7)
1
1.18
100µm
High solid aliphatic polyurethane finish
80µm
1.55
(Based on information extracted from ‘A Corrosion Protection Guide: For steelwork exposed to atmospheric environments’, see Bibliography) Notes 1. Coating system durability given in the table is based on practical experience. It is the expected life, in years, before first major maintenance. This is taken as degradation level Ri3 from ISO 4628 Part 3 (1% of surface area rusted). It should be noted that this does not imply a guarantee of life expectancy. In coastal areas, the coating life expectancy may be reduced by up to 30%. 2. The durability of galvanized steelwork is derived from the figures in BS EN ISO 14713. 3. Galvanizing should be carried out to Standard BS EN ISO 1461. 4. Where painting of galvanized steelwork is required for aesthetic or other reasons, suitable systems from ISO 12944 may be used. 5. The thickness values given for primers are the total thickness used and may include a prefabrication primer. 6. The relative costs given here are for guidance. There will be considerable variation that may typically be +/- 50% for a variety of reasons. Quotations should be obtained before making the final selection of the protective treatment. 7. It should be noted that the colour of micaceous iron oxide (MIO) is limited. 8. Environmental categories are based on those given in ISO 12944 and ISO 9223.
Figure 18. Guildford 946 space Car Park adjacent to railway and local housing
Figure 19. Aylesbury 600 spaces on 5 levels developed by Safeway Stores plc for Aylesbury Vale District Council
Steel-framed car parks 19
Refurbishment One of steel's major advantages is the ease with which it can be refurbished and adapted. Car parks in steel are no different in this respect. Where examples can be found they have been refurbished with minimal expense and great success as at the refurbished Waitrose car park at Weybridge.
Before refurbishment
After refurbishment
Refurbished interior Figure 20. Waitrose car park at Weybridge.
20 Steel-framed car parks
Aesthetic design Steel car park structures have been designed to accept all types of external cladding. Examples include Plastisol sheets as at Poole, steel mesh panels as at Aldershot, steel mesh and fins at Milton Keynes and brick as at Aylesbury, Guildford and Tallaght. There are various steel cladding systems ranging from the simple sheet to sophisticated composite panels. All are compatible with the steel frame. Brick cladding of steel frames is well proven for offices, car parks and many other structures. Steel’s inherent
Figure 23. Avebury Boulevard multi-storey car park, Milton Keynes.
accuracy is a positive advantage when attaching brickwork support systems. The cladding may be designed to be load bearing as well as aesthetic. In particular crash barriers have been designed as an integral part of the cladding system. These may be load resistant (stiff) or energy absorbing (flexible). The steel frame provides an excellent interface for connection of either type.
Figure 21. Poole car park.
Figure 24. Tallaght multi-storey car park.
Figure 22. Royal Pavillion car park, Aldershot.
Steel-framed car parks 21
Commercial viability The cost per space for a basic average-sized (250 spaces) multi-storey car park is in the region of £3,000-£4,000 (2002 figures) inclusive of framework, floors, barriers, foundations and cladding. The cost of a steel frame in real terms has decreased appreciably over the last few years through greater efficiency in both the steel manufacturing and fabrication industries. The shorter construction period made possible through the use of a steel frame and consequently the earlier return on investment increases the commercial viability. The elimination of fire protection costs has had a major influence in making a steel-framed car park one of the most competitive options available.
Midsommer Boulevard car park Milton Keynes
Latest developments
Latest developments Demountable car parks The exponential upward trend in the use of cars in the UK is resulting in the need to provide a greater number of car parks. Large companies and institutions especially, have a growing need for parking facilities. This need may be met in many cases by the use of demountable structures, to give an eminently flexible solution to the parking problem. Steel is considered to be the only practical solution that can be constructed as demountable. The car park at Luton is an example of a car park, which could be demountable with some minor modifications.
Figure 25. Simple car park in Luton
Wholly automatic multi-storey car parks This form of car park takes half the volume of a conventional car park to store the same number of cars. This is because these steel-framed car parks do not require access ramps or roadways within the car storage area. The driver parks the cars on a robot trolley within an entrance module. From this point the trolley takes the car to an empty parking space. When the driver wants the car back, it is retrieved by a robot trolley and returned to an exit module. Construction is simply a steel framework with cladding to match the local environment. Since this form of car
Figure 26. Fully automated car park building in Istanbul
park requires less energy to run, operating costs are lower than for a conventional car park. This form of car park can be built either above or below ground.
Steel-framed car parks 23
Sizing data sheets
Sizing data sheets Car space
Assumptions
6m Aisle
Car space
appropriate for one bay of a car park
7.2m
3.6m
Beam - B
Beam A
3.6m
• Design is given for internal and edge beams where
Edge Beam
following assumptions
Beam A
• Imposed loading is taken as 2.5kN/m2 • No account is taken of pattern loading
15.9m
• Grade S355 to BSEN10025:1993 is used for all main
3 Stalls (car spaces)
Beam A
The car park layouts shown are based upon the
Car space
and secondary beam steel • Grade S275 to BSEN10025:1993 is used for all ties • Approximate weights of steel given are based on a car park 72m long x 32m wide with car parking spaces at 2.4m wide. An allowance of 4% for connections and bracing has been assumed • All in-situ concrete is normal weight, grade 50 • Beams and slabs are unpropped (vertically) • Column sizes are based on the lower length of a 4-storey car park • Beams have been chosen to give a minimum frequency of 3.0Hz • Imposed load deflection limit: Span/360 • Total load deflection limit: Span/150 • Pre-camber approximately equivalent to deflection due to dead load + 1/3 deflection due to imposed load The structural sizes presented for layouts 1 to 4 have been derived on the assumption of balanced loading and effective temporary restraint of the compression flanges during construction. For further guidance on this issue refer to SCI publication SCI-P287.
Layout 1 Floor construction: 75mm deep precast planks. Composite slab depth – 140mm overall Beam ‘A’: 610 x 229 x 101 UB, grade S355 Composite with 104 – 19mm diameter shear studs x 95mm long Camber approximately 80mm Beam ‘B’: 610 x 229 x 101 UB, grade S355 Composite with 30 – 19mm diameter shear studs x 95mm long Columns: 305 x 305 x 97 UC, grade S355 Approximate weight of steel: 45.2 kg/m2 (0.86 tonne/parking space) Overall depth of construction: 743mm
24 Steel-framed car parks
Sizing data sheets
2 Stalls (car spaces)
Beam D
4.8m
Tie
Beam D Edge Beam
3 Stalls (car spaces)
Beam C
7.2m
Tie
Edge Beam
Beam C
15.9m 15.9m
Layout 2
Layout 3
Floor construction:
Floor construction:
150mm deep hollow core precast units.
100mm deep precast planks.
Composite slab depth – 200mm overall
Composite slab depth – 150mm overall
Beam ‘C’:
Beam ‘D’:
762 x 267 x 147 UB, grade S355
610 x 229 x 125 UB, grade S355
Composite with 148 – 19mm diameter shear studs x
Composite with 104 – 19mm diameter shear studs x
120mm long
120mm long
Camber approximately 95mm
Camber approximately 85mm
Tie:
Tie:
203 x 133 x 25 UB, grade S275
152 x 152 x 23 UC, grade S275
Columns:
Columns:
305 x 305 x 118 UC, grade S355
254 x 254 x 73 UC, grade S355
Approximate weight of steel:
Approximate weight of steel:
45.2 kg/m2 (0.86 tonne/parking space)
36.2 kg/m2 (0.69 tonne/parking space)
Overall depth of construction:
Overall depth of construction:
743mm
762mm
Steel-framed car parks 25
Sizing data sheets
7.2m
Beam F
Tie
Tie
Beam F
Beam F
15.9m
3 Stalls (car spaces)
Beam E
3 Stalls (car spaces)
7.2m
Beam F
Tie
Edge Beam
Beam E
15.9m
Layout 4
Layout 5
Floor construction:
Floor construction:
210mm deep hollow core precast units.
110mm pre-cast “Montex” slabs.
Composite over 1m width
Expanding grout infill with strip waterproof membrane
Beam ‘E’:
Beam ‘F’:
610 x 210 / 305 x 152 Asymmetric Cellular Beam,
457 x 191 x 74 UB, grade S355
grade S355
Composite with 74 – 19mm diameter shear studs x
400mm diameter cells @ 600mm centres
95mm long
Top tee
– 533 x 210 x 122 UB
Camber approximately 105mm
Bottom tee
– 305 x 305 x 158 UC
Composite with 99 – 19mm diameter shear studs x
Tie:
120mm long
127 x 152 x 19 tee, grade S275
Tie:
Columns:
203 x 133 x 25 UB, grade S275
203 x 203 x 46 UC, grade S355
Columns:
Approximate weight of steel:
305 x 305 x 118 UC, grade S355
40.8 kg/m2 (0.78 tonne/parking space)
Approximate weight of steel:
Overall depth of construction:
30.2 kg/m (0.58 tonne/parking space)
567mm
2
Overall depth of construction: 819mm
26 Steel-framed car parks
Sizing data sheets
Beam H
Beam H
15.9m
7.2m 3 Stalls (car spaces)
J Beam 3.6m 3.6m
J Beam
7.2m 3 Stalls (car spaces)
Beam G
Tie 3.6m
Beam G
Beam H
Tie 3.6m
Edge Beam
Beam G
15.9m
Layout 6
Layout 7
Floor construction:
Floor construction:
Comflor 70, 1.2mm gauge
Comflor 70, 1.2mm gauge
Slab 120mm thick
Slab 120mm thick
Beam ‘G’:
Beam ‘H’:
533 x 210 x 82 UB, grade S355
533 x 210 x 82 UB, grade S355
Composite with 86 – 19mm diameter shear studs x
Composite with 86 – 19mm diameter shear studs x
95mm long
95mm long
Camber approximately 100mm
Camber approximately 100mm
Tie:
Beam ‘J’:
127 x 152 x 19 tee, grade S275
533 x 210 x 82 UB, grade S355 Composite with 30 – 19mm diameter shear studs x
Columns:
95mm long
203 x 203 x 52 UC, grade S355 Columns: Approximate weight of steel:
254 x 254 x 89 UC, grade S355
31.4 kg/m2 (0.60 tonne/parking space) Approximate weight of steel: Overall depth of construction:
37.0 kg/m2 (0.71 tonne/parking space)
648mm Overall depth of construction: 648mm
Steel-framed car parks 27
Case studies
Case study 1 World Cargo Centre, Heathrow.
Brief
Technical information
The brief was to design a 1000-space multi-storey car
Area (suspended): 19,100m2
park for staff at Heathrow’s World Cargo Centre to suit
No of floors: 5 including the ground floor
the site constraints. The car park was to incorporate a
No of parking spaces (incl. ground floor): 1,000
small retail area at ground floor and meet the requirements of a gold standard award. It was to be durable, fit for purpose and give value for money.
Steel tonnage: 728T Construction period: 39 weeks Date completed: March 1997
Attributes • 5 levels of open single deck parking.
Design: Steel frames at 7.2m centres, 150 deep hollow core units with 75mm structural topping.
• Minimum clear headroom of 2400mm.
Façade: Aluminium Cladding
• Galvanized protection system.
Total construction costs: £3,900,000
• Waterproof membrane to top floor and first floor
Total cost per space: £3,900
retail area. • Steel vehicle impact barrier system
Total cost per m2 (including ground floor): £163 Type of contract: Design & Build Client: BAA plc
Special features The construction process was radically re-engineered to
Architect: HGP Architects
reduce cost and time and to develop what was to become
Engineer/fabricator: Bison Structures Ltd
known as the “World Class Construction Process”.
Management contractor: MACE
Efficiency and economy in the use of structural steelwork by standardisation, modularization and a simple design approach resulted from the innovative design and construction processes.
28 Steel-framed car parks
Case studies
Case study 2 Buttercrane Centre multi-storey car park, Co Down.
Brief
Technical information
The client’s brief for this project included an extension to
Area (suspended): 12,300m2
the retail area of an existing shopping center plus the
No of floors: 5 including the ground floor
provision of approximately 600 car parking spaces. The
No of parking spaces (incl. ground floor): 606
car parking areas were to be bright and welcoming to the shoppers whilst keeping within tight budget costs.
Steel tonnage: 500T Construction period: 30 weeks total
Attributes
Date completed: November 1997
• Nine levels of parking on split deck construction
Design: Pre-cast concrete slab (75mm thick) with in-situ topping on clear span steel frame using composite cellular beams and universal columns.
• Clear span construction using compositely designed, cambered cellular floor beams. High specification paintwork and good quality lighting provide a bright
Façade: Facing brickwork Total construction costs: £2,445,000
and comfortable environment • Top decks are overcoated with an elastomeric
Total cost per space: £4,035
waterproof membrane which is colour coded to
Total cost per m2 (including ground floor): £171
indicate the parking areas
Type of contract: JCT 80 – negotiated contract
• The structure and foundations were designed and
Client: Buttercrane Centre Ltd
constructed to allow for an additional two levels of car
Architect: WDR & RT Taggart
parking in the future
Engineer: WDR & RT Taggart Contractor: O’Hare & McGovern
Special features A 225mm pre-camber in the cellular beams was used for
Fabricator: Ballykine (Structural Engineers) Ltd
natural water shedding. This was provided at no
Cellular beams supply: Westok Structural Services Ltd
additional cost.
Managing agents: Lambert Smith Hampton
Steel-framed car parks 29
Case studies
Case study 3 Stockley Business Park, Heathrow.
Brief
Technical information
Stockley Park is an intensively developed business park
Area (suspended): 3,100m2
containing a mixture of buildings and surface parking
No of floors: 1 additional floor (suspended)
located near Heathrow Airport. 170 additional car
No of parking spaces (incl. ground floor): 178
parking spaces were required. The design and construction programme was very short and the
Construction period: 16 weeks
surrounding environment dictated a structure of high
Date completed: December 1995
aesthetic and constructional quality.
Design: Steel portal frames of tapered I section plate girders with tubular legs and tie rods. The deck comprises pre-cast concrete and glass panels.
Attributes
Façade: Open
• High architectural quality
Total construction costs: £1,200,000
• Pre-fabrication allowed very rapid design and
Total cost per space: £6,742
construction (26 weeks from concept to completion) • Piled foundations were used because of the difficult ground conditions • Open design improves the safety of the environment,
Total cost per m2 (including ground floor): £190 Type of contract: Traditional Client: BP Properties Ltd
enhanced by metal halide lighting and improved all-
Architect: Broadway Malyan
round observation
Engineer: Ove Arup & Partners
• Narrow columns save floor space and allow very tight stall widths to be used • Slim pre-cast and glass floor reduced the height and access ramp length Special features • Clear span construction allowed the car park to be built without losing ground floor parking. • Very tight spacing of bays at 2.2m • Marine Styling.
30 Steel-framed car parks
Main contractor: Try Construction Ltd Fabricator: Dyer (Structural Steelwork) Ltd
Case studies
Case study 4 Bradford city centre multi-storey car park.
Brief
The use of VCM resulted in minimum cut and fill
The Client’s brief for this project was to produce a
operations and idealized internal circulation without
modern, safe car park on a restricted site, to service the
conflicting zones.
needs of shoppers visiting Bradford city centre. The car park was to provide around 430 spaces next to the
The deck construction comprises self-finished Trideck
existing Co-op store, Sunwin House. After being in the
units, the designs of which are also the property of Hill
planning stages for a number of years Clugston
Cannon (UK) LLP, subject to a UK patent, and are
managed to bring in some innovative value engineering
available for use under licence.
ideas to take the project through to reality. Attributes • 7 levels of parking utilising a Vehicle Circulation Model (VCM) construction technique. • A combination of the steel frame and pre-cast decks
Technical information Area (suspended): 9456m2 No of floors: 7 including the ground floor No of parking spaces (incl. ground floor): 432
has enabled a lightweight easily constructed car park
Steel tonnage: 410T
on a very restricted city centre site.
Construction period: 48 weeks
• The use of clear span construction and open sides to
Date completed: October 2003
the car park give a light and open environment in which to park. A high level of low energy lighting contributes to the enhancement of the environment.
Design: Pre-cast units laid on the steel frame Façade: Insulated cladding, mesh panels, low level facing blockwork
• Cost effective design solution.
Total construction costs: £3,590,000
• Clear span construction using compositely designed,
Total cost per space: £8,310
cambered cellular floor beams. • The clear span construction has helped to provide a safe environment in which to park.
Total cost per m2 (including ground floor): £325 Type of contract: Design and Build Client: United Co-Operatives
• Top decks are overcoated with an elastomeric waterproof membrane which is colour coded for userfriendly parking.
Architect: Bowman Riley Engineer: BSCP Parking consultant: Hill Cannon (UK) LLP
Special features
D&B main contractor: Clugston Construction
As an alternative to a split level layout the VCM
Fabricator: Caunton Engineering
circulation system was adopted. This system is the property of Hill Cannon (UK) LLP, Royal Chambers, Station Parade, Harrogate, is subject to a UK patent no GB2 269 610 B and is available for use under licence.
Steel-framed car parks 31
Case studies
Case study 5 The Parishes multi-storey car park, Scunthorpe.
Brief
property of Hill Cannon (UK) LLP, Royal Chambers,
Parking facilities are a strategic element of ‘The
Station Parade, Harrogate, is subject to a UK patent no
Parishes’, a £40 million redevelopment of Scunthorpe
GB2 269 610 B and is available for use under licence. The
Town Centre. The ground plus four level 700 space car
use of VCM resulted in minimum cut and fill operations
park provides safe, secure parking for shoppers, patrons
and idealized internal circulation without conflicting zones.
of the 7 screen cinema complex and other town centre amenities and facilities.
Designed to comply with the requirements of the AA/Association of Chief Police Officers ‘Secure Car Park
Attributes
Award’ scheme.
• 4 levels of parking utilising a Vehicle Circulation Model (VCM) construction technique • A combination of the steel frame and pre-cast hollow core plus structural topping decks has resulted in a lightweight easily constructed car park on the site of an existing surface car park • The use of clear span construction and open sides
An enclosed link bridge at second floor level provides sheltered access to a terrace area, the main retail elements and the cinema complex Technical information Area (suspended): 11,900m2
create a light and open environment. A high level of
No of floors: 5 including the ground floor
low energy lighting and CCTV surveillance contributes
No of parking spaces (incl. ground floor): 700
to the enhancement of the environment
Steel tonnage: 510T
• Circa 30 disabled spaces, motorcycle and cycle parking • Office, Shopmobility and storage facilities are
Construction period: 48 weeks Date completed: October 2002
incorporated at ground level • Curtain wall glazing creates light, airy feel to stairs
Design: Pre-Con pre-cast units on the steel frame
• Cost effective design solution
Façade: Steel cladding, curtain walling and low level facing blockwork
• Clear span construction using compositely designed,
Total construction costs: £3,000,000
cambered cellular floor beams • The clear span construction has helped to provide a safe environment in which to park • Top decks are overcoated with an elastomeric
Total cost per space: £4,286 Total cost per m2 (including ground floor): £202 Type of contract: Design and Build Client: Quintain
waterproof membrane which is colour coded for userfriendly parking
Architect: CDA Architects, Brighton Engineer: Ward Cole, Lincoln
Special features
Parking consultant: Hill Cannon (UK) LLP
As an alternative to a split level layout the VCM
Contractor: Clugston Construction
circulation system was adopted. This system is the
Fabricator: Conder Structures
32 Steel-framed car parks
Case studies
Case study 6 Ipswich station multi-storey car park.
Brief The brief was to design and build a 435 space
• A wide range of elevational finishes to compliment any surrounding local environment.
multi-storey car park to service rail commuters. The car park was designed to blend in with the adjacent
Construction was undertaken adjacent to a live railway
Victorian architecture of the listed station building and
line. Furthermore, the station remained operational
surrounding private residences. The car park was also
throughout construction, and Bourne Parking carefully
designed for, and subsequently successfully achieved,
managed the interface with general public, commuters
the Secured Car Park Award. The project was won in a
and station traffic.
competitive tender scenario. Attributes
Technical information
• 7 split levels of parking.
Area (suspended): 7,000m2
• All steel components fully galvanised to 85 microns DFT.
No of floors: 7 including the ground floor
• High performance polymer modified asphalt
No of parking spaces (incl. ground floor): 435
waterproof system to top floor. • Untensioned corrugated profile safety barrier. • High quality architectural appearance including in-situ
Steel tonnage: 400T Construction period: 36 weeks Date completed: October 2001
brickwork and metal cladding. Design: 16m clear span Montex structural steelwork frame and 110mm deep Montex precast concrete floor units.
Special features The multi-storey car park was based upon Bourne
Façade: Brickwork and architectural metalwork Total construction costs: £2,600,000
Parking’s unique prefabricated Montex modular technology, which provides the following key benefits for multi storey car parks:
Total cost per space: £5,977 Total cost per m2 (including ground floor): £265 Type of contract: Design and Build
• High quality factory produced building solutions.
Client: Anglia Railways/Railtrack
• User friendly and safe clear span column free layouts
Architect: Charter
that meet the recommendations of the Secured Car Park Award.
Engineer: Whitby Bird & Partners Contractor: Bourne Parking Ltd
• Fast track construction techniques to ensure the shortest possible programme.
Fabricator: Bourne Parking Ltd
• Phased construction and planned logistical management for minimal disruption to existing facilities. • Reduced whole life cost of the building as a result of low, long-term maintenance requirements.
Steel-framed car parks 33
Bibliography
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BS 6399: Part 1: 1999 Code of practice for dead and
Parks" British Steel General Steels, Redcar. UK July
imposed loads.
1989. BS 6472: 1992 Guide to evaluation of human exposure Murray, T.M., Floor vibration testing and analysis of
to vibration in buildings.
SMART BEAM floors - parking garages, Atlanta, Georgia. Report by Structural Engineers, INC for CMC
A Corrosion Protection Guide for Steelwork in
Steel Group.
atmospheric environments. Corus Construction & Industrial 2004.
I D Bennetts, D J Proe, R R Lewins, I R Thomas "Opendeck Car Park Fire Tests". BHP Melbourne Research
Design guide on the vibration of floors (P076), The Steel
Laboratories. August 1985.
Construction Institute, 1989
I D Bennetts, D J Proe, R R Lewins, I R Thomas "Fire and Unprotected Steel in Closed Car Parks". BHP Melbourne Research Laboratories 1988. "The Scranton Fire Test" American Iron and Steel Institute Brochure. Dr B R Kirby "Reassessment of the fire resistance requirements of tall, multi-storey open sided steelframed car parking structures". British Steel Swinden Technology Centre. ECCS technical note 75 "Fire Safety in Open Car Parks" Modern Fire Engineering 1993 IISI "Fire Engineering Design for Steel Structures": State of the art 1993. Eurofer "Steel and Fire Safety: A Global Approach" 1990. "Design Recommendations for Multi-Storey and Underground Car Parks" (Third edition): Institute of Structural Engineers 2002. “The inspection and maintenance of multi-storey car parks” ICE, 2002. "Architecture and steel in construction" Blanc, McEvoy, Plank: E & FN Spon & The Steel Construction Institute 1992. BS 5950 Structural use of steelwork in building. BS 6180: 1995. A code of practice for barriers in and about buildings.
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Support from CC&I
Support for the construction industry from Corus Construction & Industrial Guidance on the design and use of structural sections and plates. Corus provides free advice to the construction industry covering all aspects of the design, specification and use of its range of construction products. Corus Construction and Industrial manufactures structural sections and plates for building and civil engineering applications. Advice is provided by our team of qualified engineers with extensive experience in the design and construction of buildings and bridges. Specialist advice on fire engineering, durability and sustainability is also available. Our regional network of engineers covers the whole of the UK and Ireland and is supported by a dedicated design team based at our manufacturing centre in Scunthorpe. General enquiries on other construction products and systems manufactured by Corus will be routed to our Construction Centre who will connect you to the appropriate source of market and product expertise. You can contact us as follows: Technical Hotline +44 (0) 1724 405060 Facsimile +44 (0) 1724 404224 Literature Line +44 (0) 1724 404400 Email
[email protected] Web www.corusconstruction.com Corus Construction & Industrial Technical Sales & Marketing PO Box 1 Brigg Road Scunthorpe North Lincolnshire DN16 1BP
Steel-framed car parks 35
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